Brandt Temple is hot about Florida. At press time, his New Orleans-based Sunrise Exploration & Production Co. was planning to pull a whole-core sample through the base of the early Cretaceous Lower Sunniland in the South Florida Basin, with a second one shortly thereafter. The hope is that Lower Sunniland will show itself to be a ripe target for oil production, possibly with just vertical wells.

His 135,000 net acres are in Lee, Hendry and Collier counties, in the heart of the long-plied Upper Sunniland, which has produced 120 million barrels vertically—all oil with some solution gas—since Humble Oil Co., now known as ExxonMobil Corp., discovered it in 1943. The inland trend, which stretches from a latitude near that of Fort Myers to Miami, is a self-contained source and reservoir system sandwiched between two salt layers.

One vertical well in Sunniland history has been made in the lower section to date; in 40 years online, it produced 300,000 barrels. “That is a smoking gun if there ever was one,” Temple says. “It’s a vertical well. They never fraced it. All they had to do was perforate it. It was slightly overpressured, so it produced on its own—and with no water.”

Temple was exploration manager, Appalachian Basin, for WhitMar Exploration Co., putting together leasehold over Marcellus and Utica shales in New York, Pennsylvania and Ohio, starting in 2005. He formed his own company with the proceeds. In 2010, the Sunrise team began to investigate whether Lower Sunniland could be a new play.

“It wasn’t a stretch for us, once we saw the historical production of Upper Sunniland with wells making 4 million barrels each and, then, realizing the Lower Sunniland is the source and no one has tried to drill it horizontally. We started to get interested. The one well that produced 300,000 barrels over 40 years with no water particularly piqued our attention.”

The team analyzed cuttings data from 35 wells that penetrated the entire Sunniland section across the trend. Many were completed in the upper zone. “Everybody rolls their eyes at the old cuttings data because cuttings lose some of their organics due to evaporation and degradation over time. Plus, they’re blended cuttings, so you don’t know precisely from what depth they’re coming, which makes things tricky in laminated rocks.”

Promising is that organic-content measurements are fairly high. “Our petrophysical and geologic results indicate that the Lower Sunniland is a thick, mappable, porous, carbonate section that is laminated, highly organic, very brittle, slightly overpressured and commonly oil saturated.”

Los Angeles-based BreitBurn Energy Partners LP makes some 1,700 barrels a day of medium, sweet crude from Upper Sunniland from assets it bought from Calumet Florida LLC, a Vulcan Resources Florida Inc. company, in 2007. In 2010, BreitBurn began approaching the upper formation horizontally, with its best well coming online at an average of 1,200 barrels a day for its first 30 days, Temple says.

Besides BreitBurn’s efforts, Sunniland is lightly drilled today. Legacy production belongs to BreitBurn and to privately held, Naples, Florida-based Collier Resources LLC, the largest private mineral owner in South Florida. It manages more than 800,000 mineral acres in Collier, Lee and Hendry counties; it also has a technical partnership with Tyler, Texas-based Lake Ronel Oil Co.

Lower Sunniland most reminds Temple of the Gulf Coast Lower Smackover’s Brown Dense, which Southwestern Energy Co. is currently attempting to prove with a horizontal approach in southern Arkansas and northern Louisiana. The former is Cretaceous in age; the latter, Jurassic. “But they’re the same sort of organic-rich, thick, limey marlstone and mudstone,” Temple says. “They’re both black, but they aren’t shale; they’re carbonates like the Utica and Eagle Ford. Our initial, proprietary measurements on Sunniland are 85% to 90% carbonate, and we’ve had samples come back at between 8% and 12% total organic content, just from the cuttings.”

Also, Lower Sunniland is the source rock for Upper Sunniland, as Lower Smackover is for Upper Smackover. “That work has already been done. It’s proven. It’s in the history books.

“I expect that, even though they are off in age a bit, the Brown Dense is your best analog to Lower Sunniland right now. This is an overlooked, under-drilled basin ripe for some modern technology.”